1. Field of the Invention
This invention relates to scanning of plain paper documents and more specifically relates to an apparatus for and methods of feeding and scanning plain paper documents and communicating the scanned data to a host computer.
2. Related Art
The ability to scan plain paper documents and store the scanned data in a format such that a host computer can build a humanly definable image and reproduce the document at will is essential in today""s society of paperless and seamless computerized networks. It is also essential that a host computer have the ability to interpret the scanned data in order to establish the content of the document to perform secondary functions. Also, because of the various specific applications and operating environments and because of the varying formats of hard copy plain paper documents, it is essential that any apparatus for or method of scanning is flexible and adaptable to various hardware interfaces. The apparatus must fit within an allotted space, therefore, a small profile is desirable. The document may vary in length and width depending on the specific document to be scanned and the document may be single-sided or double-sided. Also, most users of scanners are not trained computer or electronic hardware technicians, and many have never used such a device or have used them infrequently. Therefore, the operation of any scanner should be simple, straight forward and user friendly.
Flatbed scanners are commonly used for many applications. However, flatbed scanners are neither compact in size, nor can they be oriented in any other manner other than in an upright position with the scan window face up. Also, flatbed scanners do not provide double sided scanning. There are traction feed scanners that are more compact in size than flatbed scanners, but double-side scanning is not typically a standard feature, nor can the scanner operate with accurate traction feed when oriented other than in an upright position. If the scanner is oriented in any other manner than in an upright position, it is likely that the proper traction pressure between the traction means and the paper document will not be maintained, therefore; it is likely that a misfeed or a corrupted scan image will occur. There are also hand held scanners; however hand held scanners result in a lesser quality image, and the hand held scanner will be unable to house a conventional controller board for special image data manipulation functions or for interfacing with a host computer. Also, a typical hand held scanner is likely not able to scan an entire full-page document without multiple passes of the scanner. It is noted that scanners are sometimes only a small part of an overall document handling system. The scanners discussed above other than the hand held scanner require an upright orientation.
It is in view of the above problems that the present invention was developed. It is an object of this invention to provide a plain paper document scanner that is compact in size, but which provides a high resolution double-sided image scan of documents of varying size, and a scanner which is user friendly and sufficiently flexible so that both the scanner and paper can be positioned in varying orientations and still operate.
It is also an object of this invention to interpret the scanned data and communicate it to a host computer.
The invention satisfies the above objectives by providing a method and an apparatus for double-sided scanning. The double-sided scanner comprises two basic systems. The first is the transport hardware to move the media past the image capture sensors that are diagonally offset with respect to one another. The second is the controller board that interprets the data being sent by the image capture sensors and the communications port to transfer this data to the host computer. If the user inserts a one-sided paper document in up side down or with the wrong orientation, a successful scan of the document should still be performed.
The transport is made up of a DC powered stepper motor, two pinch rollers, two image capture sensors (image scanners), and two sets of optical sensors (paper motion sensors) to control the turning on of the motor when paper is inserted into the scanner. The two rollers are each paired with one of the image capture sensors where each pair forms a tangential contacting relationship. The zero-gravity design of the transport system allows the scanner assembly to be oriented in any manner.
The controller board is designed with two major areas of logic. The first is the area that receives and interprets the data being captured by the image sensors. The second is the area that communicates to the host computer.